Rotor for land clearing device

ABSTRACT

A rotor for a land clearing device or forestry shredder which comprises a plurality of anchors spaced apart, offset, and arranged on a horizontal cylinder. Cutting elements are mounted between adjacent anchors, the anchors arranged such that there are no gaps between the effective areas of the cutting elements as the rotator spins. The anchors can also be arranged so that at least one cutting element is located at or near the cutting element area at all times.

BACKGROUND OF THE INVENTION

The present invention relates to a rotor for cutting and, in particular,to a rotor for cutting and clearing such things as brush, debris andsmall-diameter trees.

Land clearing devices, also referred to as forestry shredders, are usedto clear such things as utility and pipe line right-of-ways, fire lanes,construction and development sites, and recreational sites. Many priorart forestry shredders have a plurality of knives, teeth or othercutting elements hingeably mounted near the periphery of a horizontalrotor. In response to the rotation of the rotor, the cutting elementsengage and cut through the tree or other woody debris. The shreddedmaterial is then discharged and left to mulch to retard erosion anddecompose. Typically, the rotor is mounted on and driven by a heavy-dutyfull-time four-wheel drive tractor.

When the forestry shredder is cutting through light brush, it is notessential that the cutting elements be aligned such that there are nogaps between their effective cutting areas. But when larger objects suchas large diameter trees and stumps are shredded, even small gaps betweenthe cutting areas of the cutting elements can create problems. Forexample, if the cutting elements are mounted between circular disks, thedisks will rub against the uncut areas of the tree. Thus, there is aneed in the art for a rotor assembly that has no gaps between thecutting areas of the cutting elements.

Several prior art shredders have attempted to remove such gaps in theircut by mounting several cutting elements on a single pin and thenoverlapping the cutting elements on different pins such that there areno gaps as the rotor spins about its axis (see FIG. 2). Mounting severalcutting elements on one pin, however, presents several problems. If, forexample, a cutting element is broken or damaged toward the middle of therotor, several other cutting elements must be removed before the cuttingelement can be replaced. This is a time consuming and expensive process.Further, when several cutting elements rotate about a single pin, thereare several worn out or rough spots on the pin, making it difficult toremove and insert the pin. In addition, when all the cutting elements ina single row strike at once, this produces an impulse to the drive line.Because each of the pins spans substantially the entire length of therotor, the cutting elements cannot be offset such that at least onecutting element is in the cutting area at all times (see FIG. 3).Instead, all the cutting elements of a single row strike at once andthen there is a gap before the cutting elements of the next row strike.Therefore, there is also a need in the art for a rotor that allows foreasy removal and replacement of the cutting elements and solves theimpulse problem.

It is therefore the principal objective of the present invention toprovide a rotor for cutting and clearing land which improves upon orsolves the problems and deficiencies existing in the art.

Another objective of the invention is to provide a rotor that has nogaps between the cutting areas across the face of the rotor.

A further objective of the present invention is to provide a rotorhaving at least one cutting element at or near the cutting area.

A still further objective of the present invention is to provide a rotorfor clearing land that allows for the easy removal and replacement ofcutting elements.

A further object of the present invention is to provide a rotor forclearing land that is efficient in operation, economical to manufacture,and durable in use.

These and other features, objects, and advantages should become apparentto those skilled in the art with reference to the accompanyingspecification.

SUMMARY OF THE INVENTION

The foregoing objectives are achieved, in the preferred embodiment ofthe invention, by a rotor assembly comprising a cylinder, a plurality ofanchors mounted to and extending from the cylinder, and a plurality ofcutting elements each mounted between the sides of adjacent anchors. Theanchors are spaced apart and offset on the cylinder such that no gapsexist between the effective cutting areas of the cutting elements. Thispreferred embodiment eliminates any gaps in the cutting area across theface of the rotor. Further, because several cutting elements are notmounted on a single pin spanning the length of the rotor, the operatorcan easily remove the pins and independently change the cuttingelements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a tractor cutting through trees, grassand debris equipped with a rotor of the present invention.

FIG. 2 is a front elevational view of a prior art rotor.

FIG. 3 is a side elevational view of the prior art rotor of FIG. 3.

FIG. 4 is a front elevational view of another prior art rotor.

FIG. 5 is a front elevational view of the rotor of the presentinvention.

FIG. 5A is an enlarged partial view of FIG. 5 showing the placement andarrangement of the support members.

FIG. 6 is a side elevational view of the rotor of FIG. 5.

FIG. 7 is a perspective view of a cutting element of the presentinvention.

FIG. 8 is a side elevational view of several cutting elements of theprior art rotor of FIG. 4 showing the gaps between their effectivecutting areas.

FIG. 9 is a view similar to FIG. 8 showing the overlap between effectivecutting areas of the rotor of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows a forestry shredder 10 comprising a heavy-duty full timefour-wheel drive tractor 11 equipped with a preferred embodiment of therotor assembly 12 of the present invention. The rotor assembly 12 ismounted within a rotor housing 14 having a left side 16 and a right side(not shown). Supporting rails 17 are mounted below both sides of therotor housing 14 and ride at or near the ground to insure that the rotorassembly 12 remains in an appropriate position above the ground.Alignment bars 18 enable the operator of the forestry shredder 10 to seethe width of the cutting area. The alignment bars 18 also help to feedbrush and small diameter trees 19 into the cutting area of the rotorassembly 12.

FIG. 2 shows a prior art rotor 20. A plurality of teeth 22 are mountedon a single pin 24. The teeth 22 are then offset on different pins 24 sothat no gaps exist between the effective cutting areas of the teeth 22as the rotor 20 completes its rotation. Although the prior art rotor 20has the advantage of eliminating the gaps in the cutting areas acrossthe face of the rotor 20, mounting several teeth 22 on a single pin 24presents significant problems. It is difficult to remove a worn tooth 22near the middle of the rotor 20 because many other teeth 22 on the pin24 must first be removed. Further, the pin 24 becomes worn from contactwith the teeth 22 which makes removal and insertion of the pin 24 moredifficult. Furthermore, because the pins 24 span substantially theentire length of the rotor 20, the teeth 22 cannot be offset such thatone cutting element is at or near the cutting area at all times (seeFIG. 3).

FIG. 4 illustrates another prior art rotor 26. Circular discs 28 arewelded to a cylinder 30. Cutting elements 32 are hingeably mounted onpins 34 between adjacent discs 28. The pins 34 are typically held inplace by the discs 28 using cap screws 36. This prior art design isadvantageous in that one cutting element 32 can be positioned at or nearthe cutting area at all times thus eliminating the impulse problems atthe drive line. The prior art rotor 26 solves the impulse problembecause the cutting elements 32 can be closely offset without themounting pins 34 interfering with the rotation of the cutting elements32. Centrifugal force in the spinning rotor 26 holds the cuttingelements 32 out in the cutting position. If material cannot be cut, thenthe hingeably mounted cutting element 32 rotates back inside the disc 28for protection. Centrifugal force then repositions the cutting element32 immediately after passing the obstacle. This prior art rotor 26suffers, however, in that there are gaps between the effective cuttingareas of the cutting elements 32 caused by the discs 28. This isproblematic when cutting small-diameter trees and stumps as the discs 28will rub against the uncut areas of the tree or stump.

The deficiencies described in the prior art rotors 20 and 26 are solvedby the rotor assembly 12 of the present invention. As shown in FIG. 5, acylinder 40 is mounted horizontally on a shaft 42. A plurality ofanchors 44 each having a first side 43, a second side 45, and a bottomedge 47 are arranged along the periphery of the cylinder 40. The firstand second sides (43, 45) of adjacent anchors 44 are facing. Althoughthe cylinder 40 can be made from a variety of different materials, it ispreferred that the cylinder 40 be comprised of a machine cold drawntorque steel. It is also preferred that the anchors 44 be made from ahigh tensile steel with the bottom edges 47 of the anchors 44 beingwelded to the cylinder 40. As shown in FIG. 5A, support members 52 aremounted substantially orthogonal to the anchors 44 to provide additionalsupport. Each side support 52 has a side edge 51 welded to either thefirst edge 43 or the second edge 45 of the anchor 44, and a bottom edge53 welded to the cylinder 40. Similar to the prior art rotor 26 of FIG.4, a plurality of cutting elements 46 are mounted individually betweenthe facing sides of adjacent anchors 44. Each cutting element 46 ishingeably mounted between the anchors on pins 48 that are retained bycap screws 50. Preferably, the cutting elements are pinned independentlyon heat-treated alloy steel pins and retained by grade 8 cap screws. Thespinning of the cylinder 40 creates a centrifugal force that holds thecutting elements 46 out in the cutting position. If the material cannotbe cut, the cutting element 46 rotates back between the anchors 44 forprotection. Centrifugal force then repositions the cutting element 46immediately after passing the obstacle. As shown in FIG. 6, the anchors44 of the rotor assembly 12 of the present invention are arranged andoffset so that a cutting element 46 is positioned at or near the cuttingarea at all times, thereby eliminating the impulse problem to the drivesystem.

The rotor assembly 12 of the present invention improves upon the priorart rotor 26 in that the arrangement of the anchors 44 now eliminatesany gaps between the effective cutting areas of the cutting elements 46as the rotor assembly 12 rotates about the shaft 42.

FIGS. 8 and 9 illustrate one of the improvements of the rotor assembly12 of the present invention over the prior art rotor 26. As shown inFIG. 9, the cutting elements 32 are positioned such that gaps 56 remainbetween the cutting elements 32. In contrast, the design of the rotorassembly 12 of the present invention effectively overlaps the cuttingareas of the cutting elements 46 thereby eliminating any gapstherebetween (see FIG. 10).

A variety of different stirrup style cutting elements can be used withthe rotor assembly 12 of the present invention. A single edge heelrelief cutting element 46 is preferred. Double edge heel relief cuttingelements 54 which are reversible are also available (see FIG. 7).

A variety of different systems can be used to power the rotor assembly12. In the preferred embodiment, the internal combustion engine of thetractor drives a variable displacement hydrostatic pump. The variabledisplacement hydraulic pump is connected in closed circuit with a fixeddisplacement hydraulic motor. The output from the hydraulic motor inturn drives a chain mechanism or toothed belt that drives the shaft 42causing the rotor assembly 12 to spin.

In operation, the cutting action of the rotor leaves a mulch of chips onthe just-cut surface to decompose and retard erosion. For additionalclean up a pass in the opposite direction will further chip and clearany remaining materials. Discharge from the rotor assembly 12 isrestricted by the encapsulation of the rotor assembly within the rotorhousing 14.

What is claimed is:
 1. A rotor assembly for cutting and clearing brushand trees comprising:a cylinder; a plurality of anchors each having atop edge, a bottom edge, a first side, and a second side, each of saidanchors being attached to said cylinder proximate said bottom edges andextending from said cylinder with said first and second sides ofadjacent anchors facing; a plurality of cutting elements each mountedbetween said first and second sides of adjacent anchors, each of saidcutting elements cutting through an effective cutting area as saidcylinder rotates; and said anchors being spaced apart and offset on saidcylinder so that no gaps exist between said effective cutting areas ofsaid cutting elements.
 2. The rotor assembly of claim 1 wherein only oneof said cutting elements being mounted between each of said first andsecond sides of said adjacent anchors.
 3. The rotor assembly of claim 1wherein each of said cutting elements being hingeably mounted betweensaid first and second sides of adjacent anchors.
 4. The rotor assemblyof claim 1 wherein each of said cutting elements being hingeably mountedon one of a plurality of pins, each of said pins being positionedbetween said first and second sides of adjacent anchors.
 5. The rotorassembly of claim 4 wherein only one of said cutting elements beingmounted on each of said pins.
 6. The rotor assembly of claim 4 whereineach of said cutting elements having a first leg, a second leg adjacentsaid first leg, and a cutting portion between said first and secondlegs, said first and second legs each having apertures being aligned toreceive said pin.
 7. The rotor assembly of claim 4 wherein said cuttingelement extends radially from said pin following the rotation of saidcylinder.
 8. The rotor assembly of claim 1 wherein said anchors and saidcutting elements being spaced apart and offset so that at least one ofsaid cutting elements at or near said brush and trees as said cylinderrotates.
 9. The rotor assembly of claim 1 further comprising a pluralityof support members each having a side edge and a bottom edge, said sideedge being attached to one of said first and second sides of said anchorand said bottom edge of said support member attached to said cylinder.10. In a rotor assembly for clearing brush and land having a cylinder, aplurality of anchors each having a top edge, a bottom edge, a firstside, and a second side, each of said anchors being attached to saidcylinder proximate said bottom edges and extending from said cylinderwith said first and second sides of adjacent anchors facing, and aplurality of cutting elements each mounted between said first and secondsides of adjacent anchors, each of said cutting elements cutting throughan effective cutting area as said cylinder rotates, wherein theimprovement comprises: said anchors being spaced apart and offset onsaidcylinder so that no gaps exist between said effective cutting areasof said cutting elements.